Problem: Rewrite the equation by completing the square. $x^{2}+18x+80 = 0$ $(x + $
Solution: Begin by moving the constant term to the right side of the equation. $x^2 + 18x = -80$ We complete the square by taking half of the coefficient of our $x$ term, squaring it, and adding it to both sides of the equation. Since the coefficient of our $x$ term is $18$, half of it would be $9$, and squaring it gives us ${81}$. $x^2 + 18x { + 81} = -80 { + 81}$ We can now rewrite the left side of the equation as a squared term. $( x + 9 )^2 = 1$